The present invention relates to packages for storing components of an admixture in separate compartments and then admixing those stored components inside the package when the admixture is to be used. More specifically, the invention relates to packages of the foregoing type for use in mixing medical solutions, food ingredients, and so forth.
A variety of medical solutions are stored in flexible plastic packages. Such medical solutions can include, for example, parenteral, enteral, dialysis solutions, nutrients and pharmacologic agents, including gene therapy and chemotherapy agents. However, a number of issues can limit the ability to store at least certain medical solutions. For example, due to stability, compatibility or other concerns, a number of medical solutions cannot be premixed. Rather, the individual components must be stored separately. Typically these components are either stored in separate packages and admixed before use, or are stored in separate compartments of a flexible package and then mixed prior to use. For example, amino acids and dextrose solutions require stored in separate packages or compartments.
One of the disadvantages of storing components in separate packages or containers and then mixing them together is that the mixing process can compromise sterility of the system and/or process. Additionally, such a mixing process creates a labor-intensive process. Still further, it is possible for mistakes to occur during the admixing process due to the amount of solution to be added from the separate packages into the final container for the patient.
To deal with the disadvantages of separate packages, it is known to provide flexible packages that include multiple chambers. To this end, such packages have an interior that defines two or more chambers. One way to create such packages is with a heat seal that divides the interior into two chambers. The seal between any two compartments must be able to withstand external stresses. Such stresses can include pressure that may be applied to one or more of the chambers from, for example, squeezing thereof or accidentally dropping the bag. Therefore the seal must be sufficiently strong, yet not so strong that it is not possible to mix the solutions contained therein.
U.S. Pat. No. 6,319,243 discloses a multi-chamber package that can be used to house multiple liquid components that are to be stored separately prior to use. Peelable seals are provided between adjacent chambers. The peelable seals allow for the selected opening of the chambers to allow for the selective mixing of the liquids contained therein. The walls of the package are made of a film laminated having four layers. The innermost layer is a sealant layer constructed of: (1) a bulk polyolefin (preferably, a polypropylene-ethylene copolymer) that melts at a temperature below the melting temperature of the outermost layer (made, e.g., of polyester material); and (2) a thermoplastic elastomer. For example, the sealand layer may include SEBS and ethylene polypropylene. The next innermost layer made of a RF-responsive polymer, such as EVA copolumer. The sealant layer is adjacent the solution side of the package. When the opposing sealant layers are bonded, a peel seal is formed between adjacent compartments. When that peel seal is ruptured, communication is provided between chambers. As constructed the four-layer film has at least one RF-responsive layer and one non-RF-responsive layer, to wit, the sealant layer. To create the seals, a RF field heats a seal bar, which heats the RF-responsive layer, which in turn heats the non-RF responsive sealant layer to soften, but not liquefy, the latter. A resulting cohesive bond develops from contact between the sealant layers of the opposing walls of the package, but fusion between the layers, which can cause permanent bonding, does not occur. To form the peelable seal using radio frequency welding or other forms of heating sealing technology, a seal bar is used.
As flexible barrier packages for consumer goods have continued to evolve and gain consumer acceptance in the world market, manufacturers of heat sealable packaging films have developed many specialty products with consumer convenience and practicality in mind. The easy open package is one such innovation. These types of film products are designed to provide hermetic heat seals with a calculated strength.
Existing methods of producing easy-open flexible packages include sealing together two different types of films under carefully controlled conditions. The resulting heat seal is a thermoplastic adhesive bond that can be pulled apart. Such an easy open seal may be described as an “adhesive rupture” mechanism. An example of such a seal is the bond that may be formed between a low-density polyethylene film sealed to a rubber-modified high-density polyethylene film. Peelable heat seals of this type require the use of two distinct materials.
Another method of producing peelable heat seals involves the use of “cohesive rupture” films. These films form peelable seals when sealed to themselves or to a standard packaging film made from a compatible polymer. The peel mechanism is created at the time of extrusion. The film sealant layer is comprised of a homogenized blend of various heat-sealable, non-heat-sealable, and compatible polymers that will not form a solution. The polymer matrix adjacent the heat area has a calculated cohesive strength. As the heat seals are pulled apart, the polymer matrix splits. The strength of the obtained heat seal may be altered by the exact formula percentages utilized in the homogenized blend. A further benefit of such a system is the visible evidence that a hermetic seal has been produced as witnessed by the transfer of material upon opening.
For example, U.S. Pat. No. 6,245,176 discloses a flexible package having compartments seperated by a “cohesive rupture” peel seal. A layer of peel seal material is applied as a coating along a zone on an inner layer of a plastic laminate, the inner layer comprising polyethylene and the substrate comprising polyester. The peel seal material contains 5 to 20 percent polybutylene by weight. The peel seal material is applied by heat sealing using a sealing bar. This substrate, zone-coated with peel seal material, is then used to produce a two-compartment mixing package. The zone-coated film is overlaid with a second layer of polyethylene film supported by a polyester substrate. The polyethylene sealant layers are confronting. Side heat seals and a center peel seal are formed. Two distinct compartments are defined by the upper and lower film walls and the side seals, and separated by the peel seal.
There is a need for a package that has an interior peel seal separating adjacent compartments and that can be manufactured inexpensively.